/**
 * @file
 * This is the IPv4 address tools implementation.
 *
 */

/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Adam Dunkels <adam@sics.se>
 *
 */

#include "lwip/opt.h"

#if LWIP_IPV4

#include "lwip/ip_addr.h"
#include "lwip/netif.h"

/* used by IP4_ADDR_ANY and IP_ADDR_BROADCAST in ip_addr.h */
const ip_addr_t ip_addr_any = IPADDR4_INIT(IPADDR_ANY);
const ip_addr_t ip_addr_broadcast = IPADDR4_INIT(IPADDR_BROADCAST);

/**
 * Determine if an address is a broadcast address on a network interface
 *
 * @param addr address to be checked
 * @param netif the network interface against which the address is checked
 * @return returns non-zero if the address is a broadcast address
 */
u8_t
ip4_addr_isbroadcast_u32(u32_t addr, const struct netif* netif)
{
	ip4_addr_t ipaddr;
	ip4_addr_set_u32(&ipaddr, addr);

	/* all ones (broadcast) or all zeroes (old skool broadcast) */
	if((~addr == IPADDR_ANY) ||
	        (addr == IPADDR_ANY)) {
		return 1;
		/* no broadcast support on this network interface? */
	} else if((netif->flags & NETIF_FLAG_BROADCAST) == 0) {
		/* the given address cannot be a broadcast address
		 * nor can we check against any broadcast addresses */
		return 0;
		/* address matches network interface address exactly? => no broadcast */
	} else if(addr == ip4_addr_get_u32(netif_ip4_addr(netif))) {
		return 0;
		/*  on the same (sub) network... */
	} else if(ip4_addr_netcmp(&ipaddr, netif_ip4_addr(netif), netif_ip4_netmask(netif))
	          /* ...and host identifier bits are all ones? =>... */
	          && ((addr & ~ip4_addr_get_u32(netif_ip4_netmask(netif))) ==
	              (IPADDR_BROADCAST & ~ip4_addr_get_u32(netif_ip4_netmask(netif))))) {
		/* => network broadcast address */
		return 1;
	} else {
		return 0;
	}
}

/** Checks if a netmask is valid (starting with ones, then only zeros)
 *
 * @param netmask the IPv4 netmask to check (in network byte order!)
 * @return 1 if the netmask is valid, 0 if it is not
 */
u8_t
ip4_addr_netmask_valid(u32_t netmask)
{
	u32_t mask;
	u32_t nm_hostorder = lwip_htonl(netmask);

	/* first, check for the first zero */
	for(mask = 1UL << 31 ; mask != 0; mask >>= 1) {
		if((nm_hostorder & mask) == 0) {
			break;
		}
	}

	/* then check that there is no one */
	for(; mask != 0; mask >>= 1) {
		if((nm_hostorder & mask) != 0) {
			/* there is a one after the first zero -> invalid */
			return 0;
		}
	}

	/* no one after the first zero -> valid */
	return 1;
}

/* Here for now until needed in other places in lwIP */
#ifndef isprint
	#define in_range(c, lo, up)  ((u8_t)c >= lo && (u8_t)c <= up)
	#define isprint(c)           in_range(c, 0x20, 0x7f)
	#define isdigit(c)           in_range(c, '0', '9')
	#define isxdigit(c)          (isdigit(c) || in_range(c, 'a', 'f') || in_range(c, 'A', 'F'))
	#define islower(c)           in_range(c, 'a', 'z')
	#define isspace(c)           (c == ' ' || c == '\f' || c == '\n' || c == '\r' || c == '\t' || c == '\v')
#endif

/**
 * Ascii internet address interpretation routine.
 * The value returned is in network order.
 *
 * @param cp IP address in ascii representation (e.g. "127.0.0.1")
 * @return ip address in network order
 */
u32_t
ipaddr_addr(const char* cp)
{
	ip4_addr_t val;

	if(ip4addr_aton(cp, &val)) {
		return ip4_addr_get_u32(&val);
	}

	return (IPADDR_NONE);
}

/**
 * Check whether "cp" is a valid ascii representation
 * of an Internet address and convert to a binary address.
 * Returns 1 if the address is valid, 0 if not.
 * This replaces inet_addr, the return value from which
 * cannot distinguish between failure and a local broadcast address.
 *
 * @param cp IP address in ascii representation (e.g. "127.0.0.1")
 * @param addr pointer to which to save the ip address in network order
 * @return 1 if cp could be converted to addr, 0 on failure
 */
int
ip4addr_aton(const char* cp, ip4_addr_t* addr)
{
	u32_t val;
	u8_t base;
	char c;
	u32_t parts[4];
	u32_t* pp = parts;

	c = *cp;

	for(;;) {
		/*
		 * Collect number up to ``.''.
		 * Values are specified as for C:
		 * 0x=hex, 0=octal, 1-9=decimal.
		 */
		if(!isdigit(c)) {
			return 0;
		}

		val = 0;
		base = 10;

		if(c == '0') {
			c = *++cp;

			if(c == 'x' || c == 'X') {
				base = 16;
				c = *++cp;
			} else {
				base = 8;
			}
		}

		for(;;) {
			if(isdigit(c)) {
				val = (val * base) + (u32_t)(c - '0');
				c = *++cp;
			} else if(base == 16 && isxdigit(c)) {
				val = (val << 4) | (u32_t)(c + 10 - (islower(c) ? 'a' : 'A'));
				c = *++cp;
			} else {
				break;
			}
		}

		if(c == '.') {
			/*
			 * Internet format:
			 *  a.b.c.d
			 *  a.b.c   (with c treated as 16 bits)
			 *  a.b (with b treated as 24 bits)
			 */
			if(pp >= parts + 3) {
				return 0;
			}

			*pp++ = val;
			c = *++cp;
		} else {
			break;
		}
	}

	/*
	 * Check for trailing characters.
	 */
	if(c != '\0' && !isspace(c)) {
		return 0;
	}

	/*
	 * Concoct the address according to
	 * the number of parts specified.
	 */
	switch(pp - parts + 1) {

		case 0:
			return 0;       /* initial nondigit */

		case 1:             /* a -- 32 bits */
			break;

		case 2:             /* a.b -- 8.24 bits */
			if(val > 0xffffffUL) {
				return 0;
			}

			if(parts[0] > 0xff) {
				return 0;
			}

			val |= parts[0] << 24;
			break;

		case 3:             /* a.b.c -- 8.8.16 bits */
			if(val > 0xffff) {
				return 0;
			}

			if((parts[0] > 0xff) || (parts[1] > 0xff)) {
				return 0;
			}

			val |= (parts[0] << 24) | (parts[1] << 16);
			break;

		case 4:             /* a.b.c.d -- 8.8.8.8 bits */
			if(val > 0xff) {
				return 0;
			}

			if((parts[0] > 0xff) || (parts[1] > 0xff) || (parts[2] > 0xff)) {
				return 0;
			}

			val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
			break;

		default:
			LWIP_ASSERT("unhandled", 0);
			break;
	}

	if(addr) {
		ip4_addr_set_u32(addr, lwip_htonl(val));
	}

	return 1;
}

/**
 * Convert numeric IP address into decimal dotted ASCII representation.
 * returns ptr to static buffer; not reentrant!
 *
 * @param addr ip address in network order to convert
 * @return pointer to a global static (!) buffer that holds the ASCII
 *         representation of addr
 */
char*
ip4addr_ntoa(const ip4_addr_t* addr)
{
	static char str[IP4ADDR_STRLEN_MAX];
	return ip4addr_ntoa_r(addr, str, IP4ADDR_STRLEN_MAX);
}

/**
 * Same as ipaddr_ntoa, but reentrant since a user-supplied buffer is used.
 *
 * @param addr ip address in network order to convert
 * @param buf target buffer where the string is stored
 * @param buflen length of buf
 * @return either pointer to buf which now holds the ASCII
 *         representation of addr or NULL if buf was too small
 */
char*
ip4addr_ntoa_r(const ip4_addr_t* addr, char* buf, int buflen)
{
	u32_t s_addr;
	char inv[3];
	char* rp;
	u8_t* ap;
	u8_t rem;
	u8_t n;
	u8_t i;
	int len = 0;

	s_addr = ip4_addr_get_u32(addr);

	rp = buf;
	ap = (u8_t*)&s_addr;

	for(n = 0; n < 4; n++) {
		i = 0;

		do {
			rem = *ap % (u8_t)10;
			*ap /= (u8_t)10;
			inv[i++] = (char)('0' + rem);
		} while(*ap);

		while(i--) {
			if(len++ >= buflen) {
				return NULL;
			}

			*rp++ = inv[i];
		}

		if(len++ >= buflen) {
			return NULL;
		}

		*rp++ = '.';
		ap++;
	}

	*--rp = 0;
	return buf;
}

#endif /* LWIP_IPV4 */
